Replaced dash wire harness and now have a lot of codes light up on dash.

I've recently replaced the entire dashboard wiring harness on my 2021 Toyota Tacoma TRD Sport and it has resulted in a slew of codes on the dashboard, and I am not sure where to even start with each before I give in and bring it into the dealership.

I felt pretty good being able to replace the harness (thanks to this forum and all your help) and now hoping I can manage clearing the codes as much as possible on my own as well.

The dashboard alerts are:

* Lane Departure Alert Malfunction
* Pre-Collision System Malfunction
* Headlight System Malfunction
* Check Vehicle Stability Control System
* Cruise Control Malfunction
* There is also a tire pressure alert (but tires are good and aired up) and the interior lights are not working)

Any help or recommendations for a starting point would be appreciated.

 

Get a scanner to see codes. Start with checking connectors

 

Did you install OEM? What was the reason to replace the entire dashboard wiring harness? Did you cut, and splice any wires, connect wires wrong?

 

You had the battery disconnected while doing the work, correct?

 

I only had solder the headlight pigtails. The rest I used a new wiring harness to swap out the old one

 

Correct. Battery was disconnected

 

Correct. I used my vin to order a new oem harness and part number matched my old oem harness

 

What is “headlight pigtails,” why touch solder them? Maybe wrong wires? What is reason you replaced old OEM harness?

 

The previous owner had cut the headlight pigtails off and cut the wires on the head unit (radio). These are 2 different wiring harnesses. It was easier to just replace the dash wiring harness. The headlights I was able to solder new pigtails and wires. I did end up using aftermarket headlights

 

Get scanner to check codes. Any other mods the previous owner did to Tacoma, and why did person sell it?

 

Double check the connections to/from the harness are seated and correct. When I did the rear coolant pipe,on my truck I didn’t have the trans wire connector seated and got all sorts of warnings too.

 

I'll try this. Thanks!

 

Previous owner sold it because he got a new Tacoma and so he took off some parts off the old one like headlights, head unit and some miscellaneous interior plastic trim. However in doing so he did a sloppy job of cutting wires instead of just unplugging them. I know he's not the brightest (now i'm stuck fixing this mess)

 

Previous owner probraly too lazy to do things right way.